The present invention relates to a squeeze type pump, which transfers slurry such as freshly mixed concrete, and more particularly, to a squeeze type pump including pairs of squeezing rollers, which squeeze an elastic tube to elastically deform the tube and transfer slurry via the elastic tube.
A prior art squeeze type pump includes an elastic tube, which is arranged in a U-shaped manner along the inner surface of a cylindrical drum. A pair of support arms are mounted on a drive shaft that is inserted through a center of the drum. The support arms are separated from each other by an angle of 180 degrees and rotate synchronously. A pair of squeezing rollers are supported at a distal portion of each support arm by means of a support shaft and a bearing. The rollers squeeze the elastic tube from each side of its outer surface to elastically deform the tube into a flat shape.
The pairs of squeezing rollers squeeze the elastic tube to move concrete that is in front of the rollers through the tube along the revolving direction of the rollers. Furthermore, the succeeding pair of rollers revolve and squeeze the elastic tube to move concrete sealed within the tube between the preceding rollers and the succeeding rollers along the revolving direction of the rollers. Concrete is thus pumped out successively.
The squeezing rollers of the prior art pump are formed from steel and are heavy. Furthermore, since steel has high heat conductivity, the rollers quickly transmit heat, which is produced by contact between the rollers and the elastic tube, toward a shaft bore defined in each roller. This structure causes quick wear of the bearings, which are arranged between the support shafts and the squeezing rollers.
Furthermore, the prior art squeeze type pump includes a seal, which prevents leakage of concrete into a receiving recess defined in each squeezing roller to receive the bearings in case the elastic tube is ruptured. This structure increases the temperature of the receiving recess and causes early wear of the bearings.